Whose preferences determine the direction of government policy? Is it the political centre, formally known as the median or mean voter, or is government policy more responsive to socio-economic elites? This paper examines political representation in the United Kingdom on the left-right scale. Politicians face a trade-off between policy and electoral incentives. The observed policy behaviour of the British government is therefore posited as a weighted average between these conflicting interests. In contrast to previous studies this paper posits an important role for political competition in the study of unequal representation. Representation can be expected to be biased towards groups with higher incomes during safe Conservative governments. Instead, when a safe Labour government has control over the direction of policy, policy outputs are more likely to be responsive to the preferences of groups with lower incomes. Under an electorally vulnerable governing party, regardless of its ideological colour, observed policy behaviour will be skewed towards the preferences of middle incomes, or, analogously, the mean voter. These propositions are tested and affirmed with longitudinal policy- and opinion-data from 1973-2006.